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Optimism (OP) to Old Sierra Leonean Leone (SLL)

Convert Optimism to old Sierra Leonean leones at the live mid-market rate. Reverse: SLL to OP

The Old Sierra Leonean Leone is no longer in use

Old Sierra Leonean Leone (SLL) was replaced by the Sierra Leonean Leone (SLE) in 2022. For today’s money, convert OP to SLE.

1 Optimism =

3,114.08 SLL −0.80% today

1 OP = 3,114.08 SLL · 1 SLL = 0.00032112 OP

Mid-market rate, updated 05:06 UTC. Paid plans update as often as every 60 seconds. Get OP→SLL rates via API

OP to SLL over the last year

5,000.0010,000.0015,000.00Nov ’25Jan ’26Mar ’26May ’26Jul ’26Sep ’26
52-week high
17,208.75
52-week low
1,875.50
52-week average
4,541.77
Change over the year
−81.03%

Conversion tables

OP to SLL
OP SLL
1 OP 3,114.08 SLL
10 OP 31,140.80 SLL
100 OP 311,408.01 SLL
1,000 OP 3,114,080.15 SLL
10,000 OP 31,140,801.47 SLL
50,000 OP 155,704,007.34 SLL
100,000 OP 311,408,014.68 SLL
SLL to OP
SLL OP
1 SLL 0.0003211 OP
10 SLL 0.003211 OP
100 SLL 0.03211 OP
1,000 SLL 0.3211 OP
10,000 SLL 3.21122100 OP
50,000 SLL 16.05610500 OP
100,000 SLL 32.11221000 OP

Get OP→SLL rates via API

The live rate, the rate on any past day or a whole range, for SLL and 170+ other currencies, as JSON. Free plan included. See the exchange rate API.

Get a free API key API documentation 
curl https://api.currencyapi.com/v3/latest \
  -G -d base_currency=OP -d currencies=SLL \
  -H "apikey: YOUR-API-KEY"

# the rate on a past day
curl https://api.currencyapi.com/v3/historical \
  -G -d base_currency=OP -d currencies=SLL \
  -d date=2025-10-04 \
  -H "apikey: YOUR-API-KEY"

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Questions about OP to SLL

How much is 1 OP in SLL?

1 Optimism is 3,114.08 old Sierra Leonean leones at the mid-market rate of 4 October 2026, 05:06 UTC, and 1 SLL is 0.00032112 OP.

What was the OP to SLL rate over the last year?

Over the last 52 weeks 1 OP ranged from 1,875.50 to 17,208.75 SLL, 4,541.77 SLL on average.

Which exchange rate is this?

The mid-market rate: the midpoint between what currency markets pay and ask for OP/SLL, without the margin a bank or card issuer adds, so the rate you are charged is usually a little worse.