There are several types of entities thorough which offshore banking services can be realized and several types of transactions carried out by an offshore banking unit. First, I will refer to the types of legal entities and then I will enumerate the categories of offshore banking .
1. Offshore banking establishments
Offshore banking generally is realized through two categories of entities, namely: (a) offshore branches; and (b) offshore subsidiaries.
A. Offshore branches
From the legal point of view an offshore branch of a bank providing offshore banking services is usually not differentiated from the parent bank onshore. This factor makes all transfers operated to and from the parent bank onshore to be qualified as intrabranch transfers.
Regular examples of offshore branches are shell branches or booking offices. As a rule booking offices do not engage a large number of employees and the overheads are low. Also they are not actively involved in the offshore banking services per se. The booking offices participate in facilitating the transactions and operations which are arranged in other jurisdictions.
Booking offshore banking centers include such jurisdictions as Aruba, the Bahamas, the British Virgin Islands, Seychelles, 
Barbados, Cayman Islands, the Channel Islands, the Marshall Islands, the Netherlands Antilles , Turks and Caicos, and Vanuatu.
B. Offshore subsidiaries
Offshore banking can be carried out thorough the establishment of offshore subsidiaries. Comparing to offshore branches which are indistinguishable from the parent bank onshore, offshore subsidiaries from the legal point of view are autonomous entities. However they are incorporated in offshore banking unit. The parent banks onshore can fully or partially owe these entities.
2. Offshore banking transactions
Offshore banking services include three types of transactions in which offshore banking units engage, namely: (a) Eurocurrency transactions; (b) over the counter trading derivatives for risk-management speculative purposes; and (c) the underwriting of Eurobonds.
From all these types of transactions exercised by offshore banking units
Eurocurrency transactions represent the most important type of transactions. These transactions consist of Eurocurrency loans and deposits. They are realized between banks and original depositors, between banks and ultimate borrowers, and between banks within the inter-bank market. The underwriting of Eurobonds has also a significant role in the bulk of the transactions undertaken by the offshore banking units. On the other hand transactions involving the over the counter trading derivatives for risk-management speculative purposes are carried out at a lesser extent. Such transactions involve complex operations with financial instruments which require special facilities. Thus these types of transactions are carried out usually in well-develop offshore banking centers.